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HTML

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HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

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Adding Classes

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About the <head>

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. If you need things in the <head> of the document, put that code here.

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Insecure Resource

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CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit- or -moz-.

We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).

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JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient. For instance, CoffeeScript can help prevent easy-to-make mistakes and offer a cleaner syntax and Babel can bring ECMAScript 6 features to browsers that only support ECMAScript 5.

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Babel is required to process package imports. If you need a different preprocessor remove all packages first.

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About External Resources

You can apply a script from anywhere on the web to your Pen. Just put a URL to it here and we'll add it, in the order you have them, before the JavaScript in the Pen itself.

If the script you link to has the file extension of a preprocessor, we'll attempt to process it before applying.

You can also link to another Pen here, and we'll pull the JavaScript from that Pen and include it. If it's using a matching preprocessor, we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.

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HTML 

              
                <svg viewBox="0 0 0 0" style="position: absolute; z-index: -1; opacity: 0;">
  <defs>
    <linearGradient id="boxGradient" gradientUnits="userSpaceOnUse" x1="0" y1="0" x2="25" y2="25">
      <stop offset="0%"   stop-color="#27FDC7"/>
      <stop offset="100%" stop-color="#0FC0F5"/>
    </linearGradient>

    <linearGradient id="lineGradient">
      <stop offset="0%"    stop-color="#0FC0F5"/>
      <stop offset="100%"  stop-color="#27FDC7"/>
    </linearGradient>

    <path id="todo__line" stroke="url(#lineGradient)" d="M21 12.3h168v0.1z"></path>
    <path id="todo__box" stroke="url(#boxGradient)" d="M21 12.7v5c0 1.3-1 2.3-2.3 2.3H8.3C7 20 6 19 6 17.7V7.3C6 6 7 5 8.3 5h10.4C20 5 21 6 21 7.3v5.4"></path>
    <path id="todo__check" stroke="url(#boxGradient)" d="M10 13l2 2 5-5"></path>
    <circle id="todo__circle" cx="13.5" cy="12.5" r="10"></circle>
  </defs>
</svg>


<div class="todo-list">
  <label class="todo">
    <input class="todo__state" type="checkbox" />
    
    <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 200 25" class="todo__icon">
      <use xlink:href="#todo__line" class="todo__line"></use>
      <use xlink:href="#todo__box" class="todo__box"></use>
      <use xlink:href="#todo__check" class="todo__check"></use>
      <use xlink:href="#todo__circle" class="todo__circle"></use>
    </svg>

    <div class="todo__text">Do a very important task</div>
    
  </label>

  <label class="todo">

    <input class="todo__state" type="checkbox" />

    <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 200 25" class="todo__icon">
      <use xlink:href="#todo__line" class="todo__line"></use>
      <use xlink:href="#todo__box" class="todo__box"></use>
      <use xlink:href="#todo__check" class="todo__check"></use>
      <use xlink:href="#todo__circle" class="todo__circle"></use>
    </svg>

    <div class="todo__text">Another important task</div>
    
  </label>

  <label class="todo">
    <input class="todo__state" type="checkbox" />
    
    <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 200 25" class="todo__icon">
      <use xlink:href="#todo__line" class="todo__line"></use>
      <use xlink:href="#todo__box" class="todo__box"></use>
      <use xlink:href="#todo__check" class="todo__check"></use>
      <use xlink:href="#todo__circle" class="todo__circle"></use>
    </svg>
    
    <div class="todo__text">Not so important task</div>
  </label>
</div>
!

CSS 

              
                @duration: 0.8s;

.todo-list {
  background: #FFF; 
  font-size: 20px;
  max-width: 15em;
  margin: auto;
  padding: 0.5em 1em;
  box-shadow: 0 5px 30px rgba(0, 0, 0, 0.2);
}

.todo {
  display: block;
  position: relative;
  padding: 1em 1em 1em 16%;
  margin: 0 auto;
  cursor: pointer; 
  border-bottom: solid 1px #ddd;
  
  &:last-child { border-bottom: none; }
}

.todo__state {
  position: absolute;
  top: 0;
  left: 0;
  opacity: 0;
}

.todo__text {
  color: saturate(#1B4A4E,15%);
  transition: all @duration/2 linear @duration/2;
}

.todo__icon {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 100%;
  height: auto;
  margin: auto;
  
  fill: none;
  stroke: #27FDC7;
  stroke-width: 2;
  stroke-linejoin: round;
  stroke-linecap: round;
}


.todo__line,
.todo__box,
.todo__check {
  transition: stroke-dashoffset @duration cubic-bezier(.9,.0,.5,1);
}


.todo__circle {
  stroke: #27FDC7;
  stroke-dasharray: 1 6;
  stroke-width: 0;
  
  transform-origin: 13.5px 12.5px;
  transform: scale(0.4) rotate(0deg);
  animation: none @duration linear; //cubic-bezier(.08,.56,.04,.98);
  
  @keyframes explode {
    //0% { stroke-width: 0; transform: scale(0.5) rotate(0deg); }
    30% { 
      stroke-width: 3;
      stroke-opacity: 1;
      transform: scale(0.8) rotate(40deg);
      //animation-timing-function: cubic-bezier(.89,.01,.95,.51);
    }
    100% { 
      stroke-width: 0;
      stroke-opacity: 0;
      transform: scale(1.1) rotate(60deg);
      //animation-timing-function: cubic-bezier(.08,.56,.04,.98);
    }
  }
}

.todo__box { 
  stroke-dasharray: 56.1053, 56.1053; stroke-dashoffset: 0;
  transition-delay: @duration * 0.2; 
}
.todo__check {
  stroke: #27FDC7;
  stroke-dasharray: 9.8995, 9.8995; stroke-dashoffset: 9.8995;
  transition-duration: @duration * 0.4; 
}
.todo__line {
  stroke-dasharray: 168, 1684; 
  stroke-dashoffset: 168;
}
.todo__circle { 
  animation-delay: @duration * 0.7; 
  animation-duration: @duration * 0.7; 
}

.todo__state:checked {
  
  ~ .todo__text { transition-delay: 0s; color: #5EBEC1; opacity: 0.6; }
  
  ~ .todo__icon .todo__box { stroke-dashoffset: 56.1053; transition-delay: 0s; }
  ~ .todo__icon .todo__line { stroke-dashoffset: -8; }
  ~ .todo__icon .todo__check { stroke-dashoffset: 0; transition-delay: @duration * 0.6; }
  ~ .todo__icon .todo__circle { animation-name: explode; }
  
}

html { background: #ddd; }
html { height: 100%; display: flex; }
body { width: 100%; margin: auto; }
!

JS 

              
                console.clear();

setTimeout(function(){
  document.querySelector('input[type="checkbox"]').setAttribute('checked',true);
},100);
/*

// Javascript was initially used, but wasn't really necessary. Javascript droppped, but left here for archival purposes.

var todoTemplate = function(id){ 
  return `<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 25" class="todo__icon">
    <defs>
      <mask id="myMask${id}" maskUnits="userSpaceOnUse" x="0" y="0">
        <g stroke="#FFF" fill="none">
          <path class="todo__line" d="M21 12.3h168"/>
          <path class="todo__box" d="M21 12.7v5c0 1.3-1 2.3-2.3 2.3H8.3C7 20 6 19 6 17.7V7.3C6 6 7 5 8.3 5h10.4C20 5 21 6 21 7.3v5.4"/>
          <path class="todo__check" d="M10 13l2 2 5-5"/>
        </g>
      </mask>
    </defs>
    <rect fill="url(#todoGradient)" mask="url(#myMask${id})" width="100%" height="100%" />
    <circle class="todo__circle" cx="13.5" cy="12.5" r="10" />
  </svg>`
};

var todos = [ ...document.querySelectorAll('.todo') ].forEach(activateTodo);

function offsetPath(path, offset){
  var length = path.getTotalLength();
  path.style.transition = 'none';
  path.style.strokeDasharray = length + ' ' + length + offset;
  path.style.strokeDashoffset = length; 
  setTimeout(function(){ path.style.transition = null; },20);
  return length;
}

function togglePath(path, toggle, offset = 0){
  var length = offsetPath(path, offset);

  function updatePath(toggle){
    return path.style.strokeDashoffset = ( toggle ? -offset : length );
  }

  updatePath(toggle);
  return updatePath;
}

function activateTodo(todo, i){
  
  todo.insertAdjacentHTML('afterbegin', todoTemplate(i));
  
  var line = todo.querySelector('.todo__line'),
      updateLine = togglePath(line, false, 4);

  var box = todo.querySelector('.todo__box'),
      updateBox = togglePath(box, true);

  var check = todo.querySelector('.todo__check'),
      updateCheck = togglePath(check);

  var toggle = false;

  todo.addEventListener('click', function(){
    toggle = !toggle;
    updateLine(toggle);
    updateBox(!toggle);
    updateCheck(toggle);
    if ( todo.classList ) { todo.classList[ toggle ? 'add' : 'remove' ]('todo--checked'); }
  });
  
}

*/
!
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